Predictive Value of Lysophosphatidylcholine for Determining the Disease Severity and Prognosis of Elderly Patients with Community-Acquired Pneumonia

Figures & data

Figure 1 Flow diagram of patient selection and grouping in this study.

Table 1 Clinical Characteristics of Non-SCAP and SCAP Patients Before and After Propensity Score Matching Analysis

Characteristics	Unmatched Cohort			Matched Cohort
	Non-SCAP (N = 141)	SCAP (N = 67)	P value	Non-SCAP (N = 31)	SCAP (N = 31)	P value
Males (%)	81 (57.4)	48 (71.6)	0.049	16 (51.6)	21 (67.7)	0.196
Age (years)	75.04 ± 8.37	83.93 ± 9.20	<0.001	79.87 ± 9.72	80.71 ± 9.60	0.734
Underlying diseases (%)
Cardiovascular diseases (%)	92 (65.2)	53 (79.1)	0.042	28 (90.3)	25 (80.6)	0.473
Diabetes mellitus (%)	29 (20.6)	22 (32.8)	0.055	11 (35.5)	9 (29.0)	0.587
Chronic pulmonary diseases (%)	14 (9.9)	8 (11.9)	0.659	3 (9.7)	1 (3.2)	0.612
Laboratory results
WBC (×10^9/L)	7.77 (6.33–10.44)	10.67 (8.85–14.68)	<0.001	8.11 (6.25–10.35)	11.19 (8.30–15.03)	0.004
NEU (×10^9/L)	5.40 (4.21–7.73)	9.22 (7.16–12.49)	<0.001	6.50 (4.24–8.15)	9.37 (7.18–12.49)	0.001
LYM (×10^9/L)	1.29 (0.90–1.78)	0.75 (0.47–1.30)	<0.001	1.01 (0.61–1.61)	0.72 (0.40–1.12)	0.029
NLR	3.97 (2.51–9.17)	11.43 (6.63–20.82)	<0.001	5.55 (3.21–10.67)	11.43 (7.86–20.00)	0.027
CRP (mg/L)	28.94 (6.38–91.46)	53.72 (22.91–122.25)	0.004	63.13 (2.77–150.26)	52.88 (22.23–122.25)	0.782
PCT (μg/L)	0.10 (0.04–0.34)	0.52 (0.17–2.51)	<0.001	0.21 (0.07–0.70)	0.57 (0.26–3.39)	0.039
Interleukin-6 (pg/mL)	5.34 (2.77–11.36)	10.65 (5.18–17.56)	<0.001	7.41 (2.94–15.21)	10.06 (5.73–13.32)	0.435
Interleukin-8 (pg/mL)	16.62 (12.38–23.90)	26.79 (17.82–48.98)	<0.001	19.21 (14.23–29.63)	27.02 (17.82–44.09)	0.060
Day 1 LPC (ng/mL)	29.64 (23.54–36.24)	28.69 (22.79–33.65)	0.360	33.44 (26.91–37.63)	28.29 (23.50–31.35)	0.011
Day6 LPC (ng/mL)	28.89 (21.83–35.99)	22.21 (19.33–33.34)	0.038	29.17 (18.68–42.64)	21.71 (19.41–29.36)	0.035
CURB-65 score	1.00 (1.00–1.00)	3.00 (2.00–3.00)	<0.001	1.00 (1.00–2.00)	3.00 (2.00–3.00)	<0.001
PSI score	80.00 (66.50–96.00)	137.00 (122.00–164.00)	<0.001	95.00 (69.00–106.00)	136.00 (124.00–159.00)	<0.001
30-day mortality (%)	1 (0.01)	17 (25.37)	<0.001	1 (0.03)	11 (35.48)	0.001

Notes: Categorical variables are expressed as numbers (percentages); continuous variables with a normal distribution are expressed as mean ± SD; continuous variables with a normal distribution are expressed as median (interquartile range).

Abbreviations: CAP, community-acquired pneumonia; SCAP, severe community-acquired pneumonia; SBP, systolic blood pressure; DBP, diastolic blood pressure; WBC, white blood cell; NEU, neutrophil counts; LYM, lymphocyte counts; NLR, neutrophil-to-lymphocyte ratio; CRP, c-reactive protein; PCT, procalcitonin; LPC, lysophosphatidylcholine; CURB-65, confusion, uremia, respiratory rate, blood pressure, and age ≥65 years; PSI, pneumonia severity index.

Figure 2 Serum LPC levels in elderly patients with CAP. (a) Serum LPC levels of patients in the non-SCAP (blue circles) and SCAP (red squares) groups on days 1. (b) Serum LPC levels of patients in the survivor (purple circles) and non-survivor (brown squares) groups on days 1. (c) Serum LPC levels of patients in the survivor and non-survivor groups on days 1 and 6 after treatment. The data are represented as the median value.

Table 2 Binary Logistic Regression Analysis of SCAP Incidence

Variable	Univariate Analysis		Multivariate Analysis
	HR (95% CI)	P value	HR (95% CI)	P value
WBC (×10^9/l)	1.221 (1.050–1.419)	0.009
NEU (×10^9/l)	1.282 (1.083–1.518)	0.004
LYM (×10^9/l)	0.428 (0.184–0.998)	0.048
PCT (ng/mL)	1.169 (0.972–1.404)	0.097
IL-8 (pg/mL)	1.026 (0.997–1.055)	0.079
LPC (ng/mL)	0.920 (0.859–0.986)	0.018
CURB-65 score	12.304 (3.783–40.025)	<0.001	4.712 (1.292–17.191)	0.019
PSI score	1.087 (1.044–1.132)	<0.001	1.052 (1.010–1.097)	0.016

Abbreviations: CI, confidence interval; WBC, white blood cell; NEU, neutrophil count; LYM, lymphocyte count; NLR, neutrophil-to-lymphocyte ratio; PCT, procalcitonin; IL-8, interleukin 8; LPC, lysophosphatidylcholine; CURB-65, confusion, uremia, respiratory rate, blood pressure, and age ≥65 years; PSI, pneumonia severity index.

Figure 3 ROC curve analysis shows the prediction performances of LPC, PSI score, CURB-65 score, LPC + PSI score, and LPC + CURB-65 score in discriminating between SCAP and non-SCAP patients.

Table 3 Area Under the Curve Values and Thresholds of Different Parameters for Predicting the 30-Day Mortality in CAP Patients

Variable	AUC	95% CI		Sensitivity (%)	Specificity (%)	Threshold	P value
		Lower Limit	Upper Limit
WBC (×10^9/L)	0.712	0.569	0.855	91.7	51.0	>8.58	0.024
NEU (×10^9/L)	0.759	0.633	0.886	100.0	53.1	>7.08	0.006
LYM (×10^9/L)	0.539	0.336	0.743	98.0	25.0	< 0.27	0.675
PCT (ng/mL)	0.690	0.551	0.828	91.7	49.0	>0.25	0.043
IL-6 (pg/mL)	0.578	0.402	0.754	83.3	38.0	>5.97	0.402
IL-8 (pg/mL)	0.707	0.539	0.874	50.0	88.0	>43.48	0.027
LPC (ng/mL)	0.692	0.518	0.865	86.0	58.3	<24.36	0.040
CURB-65	0.768	0.643	0.892	100	46.0	>1.50	0.004
PSI score	0.906	0.827	0.985	83.3	90.0	>136.50	<0.001

Abbreviations: AUC, area under the curve; CI, confidence interval; WBC, white blood cell; NEU, neutrophil count; LYM, lymphocyte count; PCT, procalcitonin; CURB-65, confusion, uremia, respiratory rate, blood pressure, and age ≥65 years; IL-6/8, interleukin 6/8; PSI, pneumonia severity index.

Table 4 Cox Proportional Hazard Regression Analysis of Multiple Variables for Predicting the 30-Day Mortality of Elderly Patients with CAP

Variable	Univariate Analysis		Multivariate Analysis
	HR (95% CI)	P value	HR (95% CI)	P value
WBC (×10^9/L)	0.901 (0.804–1.009)	0.072
NEU (×10^9/L)	0.890 (0.790–1.002)	0.053
LYM (×10^9/L)	1.284 (0.536–3.073)	0.575
PCT (ng/mL)	0.964 (0.874–1.063)	0.464
IL-6 (pg/mL)	0.987 (0.969–1.006)	0.177
IL-8 (pg/mL)	0.964 (0.937–0.993)	0.014
LPC <24.36 (ng/mL)	8.600 (2.124–34.815)	0.003	6.212 (1.155–33.413)	0.033
CURB-65 score	0.341 (0.157–0.738)	0.006
PSI score	0.955 (0.930–0.981)	0.001	0.960 (0.937–0.985)	0.001

Abbreviations: CI, confidence interval; WBC, white blood cell; NEU, neutrophil count; LYM, lymphocyte count; PCT, procalcitonin; IL-6/8, interleukin 6/8; LPC, lysophosphatidylcholine; CURB-65, confusion, uremia, respiratory rate, blood pressure, and age ≥65 years; PSI, pneumonia severity index.

Figure 4 Kaplan–Meier survival curve analysis shows the 30-day mortality rates of elderly CAP patients stratified by high- or low-LPC levels using LPC concentration of 24.36 ng/mL as the cut-off value.